Chevy Volt batteries have caught fire. The National Highway Traffic Administration (NHTSA) is investigating, and General Motors has offered to buy Volts back from any owner who fears the electric cars will catch fire.

So does it mean the Chevy Volt is unsafe? The short answer is, no -- Volts won't be spontaneously bursting into flames on our nation's highways. Rather, according to experts we spoke with, the Volt fires prove that automotive engineers have been justified in employing elaborate and expensive cooling systems in their electric vehicles.

Chevy Volt in a side crash test, performed by the Insurance Institute for Highway Safety.

The truth is, there's always been a well-understood fire risk associated with lithium-ion batteries. "The chemistry is edgy," Donald Sadoway, professor of materials chemistry at the Massachusetts Institute of Technology, told Design News in an email. "The electrolyte is an organic liquid that is flammable, highly volatile at even moderately elevated temperature and in the presence of metallic lithium, which can form on the negative electrode at high charging rates."

Elton Cairns, a professor of chemical and biomolecular engineering at the University of California-Berkeley, explains: "In a lithium-ion battery, you've got electrodes that are tens of microns from one another. If you deform the cell case and it causes the electrodes to touch one another, there's an internal short circuit. That can cause the cell to rapidly discharge and, in so doing, heat up."

All of that might sound like a prescription for an epidemic of electric car fires, but it isn't. Why? Because of the aforementioned cooling systems. The Volt employs a fluid coolant that circulates through 1mm-thick channels machined into 144 metal plates that sit between the battery's cells. Using the coolant, the Volt draws the heat away from the core of its big battery.

Similarly, Toyota's Prius PHV, a plug-in hybrid, uses three fans for air circulation, along with ductwork, and 42 sensors to monitor the temperature of its lithium-ion battery. Virtually every manufacturer of production EVs also employs battery management systems and multiple microcontrollers to track the operation of the battery pack at every moment.

Remember, when GM first tested airbags, the prototypes kept decapitating the dummies.

The danger of any exotic chemical batteries and energy cells is well known. The Bolder TMF cell can do a similar job powering hybrids...Remember the Chrysler EXS created some time ago? Bolder uses a LEAD ACID combination with plastic shielding isolating EVERY CELL in the pack. That cell system was used in the ESX. No fires, no leakage except from the damaged cells in a collision...The amount of standard car battery electrolyte is contained in the matrix. No more than a few drops per cel actually leaks out.

Contrast that to the problems the ( re) VOLT (ing) has.

Used regular materials in power pack construction and the problem goes away.

Rod, according to Hollywood, your Pinto experience is not typical. If you do a survey of all car crashes in films or on TV, all car crashes result in fire & an explosion. This is specially true if you are a bad guy.

I think at this point we clearly don't know the complete range of risks in the Volt. Nor, re the earlier comment, do we know exactly how many Volts have been sold. We'll be keeping up with both issues in our continuing coverage on Design News; thanks for the comments and for bringing these issues to the fore.

We still don't know enough about what happened and when we do, we will report it. But too many times, stories in the newspapers and TV news about such subjects take on the apperance of a witch hunt, then they disappear. Consider Toyota's unintended acceleration "problem." Little was written when Transportation Secretary Ray LaHood said this after the NHTSA investigation: "The jury is back. The verdict is in. There is no electronic-based cause for unintended high-speed acceleration in Toyotas. Period." And what about the infamous General Motors pickup trucks -- the ones that were profiled on NBC Dateline in a story called "Waiting to Expode?" Those vehicles, too, were supposed to be death traps...until it was learned that NBC faked the explosions with remote control explosives. Again -- I repeat -- we don't yet know what happened here. And, yes, there are anomalies. So, yes, government agencies should certainly investigate this fire (or fires, as the case may be). But until we do know anything definitive, I'm siding with the engineers. For the most part, they have a good track record.

Alongside gasoline-fueled fires, a big cause of automotive deaths remains distracted driving. According to the National Highway Traffic Safety Administration (pdf download), some 33,000 deaths were caused in 2009 by drowsy driving. I don't know if there are stats yet for accidents caused by texting while driving, but I'd bet the numbers are pretty scary. That said, this stuff as well as gas are discrete from the issues raised by Lithium Ion batteries, which need to be investigated.

Good point, dgb. Consider this: A gallon of gasoline contains about 30 kWh of energy. That means that a 15-gallon gas tank holds about 450 kWh. In contrast, a Volt battery contains 16 kWh -- equivalent to about half a gallon of gas.

These batteries have caused numerous product recalls including thousands of computers and just last month I got a message from Apple recalling my 1st generation, 5 year old iPod due to battery fires!! Apparently as these units aged, they have become more susceptable to initiating fires.

As with all systems, we learn to live with risk managment, by both the provider of the product and the user of the product. However, as systems become more complex, the potential failure modes increase and the reliability decreases. Just remember that the more cells you stuff in a battery and the more electronics you pack around it and its vehicles interfaces, the higher the probability of a failure.

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